Production of textile materials



Feb. 13, 1951 w. I. TAYLOR 2,541,305

PRODUCTION OF TEXTILE MATERIALS Filed June 23, 1949 o 59] o o o o o If)I Q? FIGZ. FIG .I.

Inventor WI- TA YLOR Patented Feb. 13, 1951 PRODUCTION OF TEXTILEMATERIALS William Ivan Taylor, Spondon, near Derby,'England, assignor toCelanese Corporation of America, a corporation of Delaware ApplicationJune 23, 1949, Serial No. 100,883 In Great Britain July 2, 1948 25Claims.

This invention relates to the production of textile materials and inparticular to the production of artificial continuous filaments in theform of very heavy bundles, or tows of filaments, a form which isespecially useful for the conversion of the continuous filaments intostaple fibres.

One method of producing continuous artificial filaments is the methodknown as dry spinning, in which a film-forming liquid, e. g. a solutionof cellulose acetate in a volatile solvent such as acetone, is extrudedin the form of filaments through a spinning jet having a number of smallorifices into a gaseous setting medium in which the filaments harden. Itis anobject of the present invention to provide a dry-spinning apparatusof a form especially advantageous for the production of continuousfilaments in the form of heavy bundles or tows suitable for conversioninto staple fibres.

According to the present invention an apparatus for the production bydry spinning ofa heavy bundle or tow of continuous filaments comprises avertical spinning cell, a plurality of ranks of multi-orifice jets inthe upper part of said cell, one rank within another, each rankconsisting of a number of jets arranged round the middle of said cell,the jets of each inner rank being at a higher level than those of therank immediately outside it, and the top of the cell being stepped backso that all the jets are accessible through openings in the sides of thecell, the cell being formed at the bottom with a space common to thefilaments from all said jets, and means for collecting all saidfilaments in tow form. Thus the cell is stepped back immediately abovethe first or outermost rank of jets, to render accessible the jets ofthe second rank, within and above the first. If a third rank is providedwithin the first two, it can be disposed at a higher level than thesecond rank, the top of the cell being again stepped back immediatelyabove the second rank of jets, and so on. By these means a very largenumber of spinning jets, each producing a number of separate filaments,can be compactly accommodated in a single spinning cell occupying butlittle fioor space, while permitting ready access to each of the jetsfor servicing of the jets and for their replacement when nec essary.

In describing the invention in greater detail hereafter, reference willbe made to the accompanying drawings which show, by way of example, oneform of spinning apparatus according to the invention and in which,

Figure 1 is a front elevation, partly in section, of the spinning celland,

Figure 2 is an inverted sectional plan taken on the line 2-2 of Figure1.

The apparatus shown in the drawing comprises a vertical spinning cell Ihaving a number of multi-orifice jets 2 in the upper part thereof, thejets being arranged round the middle part 3 of the cell in two ranks 4,5, one Within the other. The jets of the inner rank 4, as shown inFigure 1, are at a higher level than those of the outer rank 5, and thetop of the cell I is stepped back at 6, immediately over the outer rank5, so that all the jets 2 of both ranks are accessible through openingsI in the side of the cell I. The cell is formed at the bottom with aspace 8, 9 common to the filaments Ill coming from all the jets 2 andmeans, generally indicated at I I, are provided beneath the cell forcollecting all said filaments in tow form.

In the preferred form of apparatus shown in the drawings, thefilament-collecting means are in the form of a single tow-collectingdevice for collecting all the filaments in the form of a single tow I2.The filaments emerge all together from a common outlet l3 at the bottomof the cell, pass through guides I4, round a flanged guide pulley I5 andon to a large drum l6 driven at constant peripheral speed so as to drawthe tow I2 out of the cell and deliver it into a coiler can I1 of thekind commonly employed in the collection of textile slivers.

In order to promote uniformity of the filaments III produced, asbetweenthe different jets 2 in the cell I it is of advantage to divide thecell, for the upper part of its length, into sub-cells 20 all openingdownwards into an undivided portion 8, 9 of the cell leading to thecommon outlet l3. For this purpose, and for general convenience inconstruction, the preferred spinning cell shown is made of square orrectangular crosssection; such a cell can readily be divided by sheetmetal partitions as at 2! to form two or more concentric ranks ofapproximately square compartments 28 each containing a single jet 2.Cells of other than square or rectangular crosssection may be used,however, e. g. of hexagonal or octagonal cross-section, and the upperparts thereof can be divided into sub-cells of rectangular or othersuitable shape.

The subdivision of the upper part of the cell in the manner describedabove is of particular advantage when the setting of the filaments I 0is effected by the evaporation of a volatile solvent therefrom, in whichcase the character of the filaments, and especially the shape of theircrosssection, is liable to be affected by small differences in theevaporative conditions obtaining in the very early stages of setting.Dividing the upper part of the cell i into sub-cells 20 reduces thelikelihood of the different jets 2 receiving substantially differentsupplies of the gaseous setting medium, serving in this instance as anevaporative medium to carry off the solvent vapours from the filaments,and prevents the setting me dium that acts on the group of filaments ii?emerging from one jet 2 being already laden with solvent vapour throughhaving been in contact with the filaments of another jet. Where settingis effected otherwise than by the evaporation of volatile so;vent fromthe filaments iii, e. g. by mere cooling of the filaments, thesubdivision of the cell is advantageous as preventing cross draughts ofsetting medium in the top of the cell which are apt to have a harmluleffect on the filaments in the early stages of their setting.

For the same purpose of promoting uniformity, each separate jet 2 can besupplied with filmiorming liquid by its own individual measuring pump sothat the total denier of the filaments from each jet is held constant.Alternatively, however, the jets in the cell may be divided into greateror smaller groups, each group being fed from a measuring pump common toall the jets of that group. The several measuring pumps, whether for-thesupply 01" individual ets or of groups of jets, are preferably disposedoutside the cell in a compact battery (not shown) conveniently situatednear the top of the cell. The filters (not shown) employed for filteringthe liquid supplied to individual jets or groups of jets are preferablydisposed close to the pumps so as to reduce as far as possible thecomplication of the arrangements in the top of the cell itself.

The jets can be supplied from the pumps and filters by pipes 23proceeding from the battery of pumps and entering the cell by a centralspace 3 in the top of the cell, free of spinning jets and enclosed bythe inmost rank 4 of jets 2. The pipes 23 serving the outer rank 5 ofjets 2 pass through passages 23 (Fig. 2) formed in the partitions 2idividing the subcells of the inner rank 3 from one another.

If it is desirable that the liquid extruded from the jets should be hot,as is the case when the film-forming liquid is a solution of celluloseacetate in acetone and is spun into a current of cold air moving in thesame direction as the filaments and serving as an evaporative medium, itcan be heated by the provision of a steam coil 25, or other heatingmeans, disposed in the central space 3 in the top of the cell by whichthe pipes 23 supplying the jets 2 enter the cell. The top of the cell lis provided with heavy lagging 26 to retain the heat in thhe centralspace 3, and the length of run of the pipes 23 through this space isrelied on to enable the film-forming liquid passing through them to beheated to the required degree. This provides an extremely economicalmethod of heating. Alternatively, however, the liquid can be heated byimmersing the pumps, and/or the filters, in the heated baths or jackets.The pipes 23 leading from the filters to the jets 2, can also bejacketed and, where a single pump serves a group of jets, thetemperature of the header supplying the several jets of each group canbe maintained by running alongside it a, parallel pipe or passagethrough which is circulated a heating medium at an appropriatetemperature.

The length of the spinning cell from the top to the common outlet [3 atthe bottom depends on the nature of the filaments Ill and the action ofthe setting .medium thereon, and on the linear speed of spinnin andother spinning conditions. It may vary according to the circumstances,from less than 10 feet up to thirty feet or more. The cell should in anycase be long enough for the filaments to be sufficiently set, by thetime they reach the common outlet 13, not to stick to one another asthey are brought into contact at the outlet, or in subsequent collectionand storage. The division of the top of the cell into sub-cells 28 mayextend down the cell to a distance of the order of two to five feetaccording to the total length or" the cell.

The common outlet l3 at the bottom of the spinning celli I is.preferably led into by causing the walls 2.! of the bottom part 9 of thecell to converge to a small area at 28 in which the outlet is provided.The bottom part 9 of the cell l is thus of the form of an invertedpyramid, whose apex is truncated to form the outlet area. In order tofacilitate the passage of the filaments-l0 to the outlet area,the'convergence of the walls 2? is prei'eracly such that their angle tothe horizontal is greater than the angle of repose of filaments restingthereon. In this way, the filaments It extruded from: the jets 2,falling vertically and striking the converging walls,2l, automaticallyfind their Way to the outlet area 28 under gravity. The common outletmay be further reduced in area by providing a pair of swing doors 29which can be opened to facilitate the initial emergence of thefilaments, but subsequently closed so as to leave a reduced opening-l3.The guides ill can be in the form of forked guides mounted on thedoors-253 so asto engage the filaments l8 and guide them into the formof a com pact tow l2 when the doors areclosecl. Springs 39 can beprovided to hold thedoors 29 in the open or closed position. Windows 22'may be provided in the walls Zl for the illumination and inspectionofthe inside of thecell.

The gaseous setting medium, contained with-' in the cell i for thepurpose of setting the filaments ill after they are extruded, ispreferably in the form of a current of air flowing in thedirection ofthe extrusion of the filaments Illand drawn off from the lower partoi'the-cell I. Thus, air may enter at the topof the cell through theopenings which give access to the-spinning jetsZ or through suitableslots or other apertures. in access doors covering the said openings.f'he air passes down the cell and is withdrawn through a series ofdraw-oil pipes 31 disposed in an enlargement 32 of the cell iimmediatelyabove the sharply tapered part e atthe bottom of the cell.The pipes 3| communicate with a suction duct 33 which extends round thecell and is connected by a duct 34 to a suction main: Openings may alsobe provided close to the outlet-at the bottom of the cell, as, at 35-,where there are shown gauze-covered openings,- one on each; wall 2? ofthe tapered part 9 of the cell, each opening 35 communicating with acommon pipe 36., The pipe 38 has aconnection 3? by means ofjwhich airmay be sucked off from, or additionalair introduced into, theneighbourhoed of the common outlet. By these means the taperedpartll canbe continuously swept by-acurrent of air.

In order to reduce the volume of the -cell that is traversed by the.current of air drawn-off through the pipes 3!, the middle of the cellmay be occupied by a closed shell '38, extending over the part 8 of thelength of the cell, i. e. from the central space 3 at the top of thecell lto the level of the enlargementqEZ. The shell 38 isinot incommunication with the, part. of the. cell l through which the filamentsl pass, although, if desired, provision may be made for drawing 01f aircentrally of the cell l by a suction pipe (not shown) extending up themiddle of the shell 38.

The invention is of especial importance in relation to the spinning offilaments of cellulose acetate. It may, however, also be applied to thespinning of other film-forming materials capable of constituting thebasis of a film-forming liquid that can be spun into filaments and setby the action on the filaments of a gaseous setting medium. Examples ofother film-forming materials than cellulose acetate that can be used insolution in volatile solvent, are other esters and mixed esters ofcellulose such as cellulose propionate, cellulose butyrate, celluloseacetate propionate and cellulose acetate stearate, and cellulose etherssuch as ethyl and benzyl cellulose.

Having described my invention, what I desire to secure by Letters Patentis:

1. An apparatus for the production by dry spinning of a heavy bundle ortow of continuous filaments, said apparatus comprising a verticalspinning cell, a plurality of ranks of multi-orifice jets in the upperpart of the cell, one rank within another, each rank consisting of anumber of jets arranged round the middle of the cell, the jets of eachinner rank being at a higher level than those of the rank immediatelyoutside it, and the top of the cell being stepped back so that all thejets are accessible through openings in the sides of the cell, the cellbeing formed at the bottom with a space common tothe filaments from allsaid jets, and means for collecting all said filaments in tow form.

2. An apparatus for the production by dry Spinning of a heavy bundle ortow of continuous filaments, said apparatus comprising a verticalspinning cell, a number of multi-orifice jets in the upper part of thecell arranged round the middle of the cell in two ranks one within theother, the jets of the inner rank being at a, higher level than those ofthe outer rank, and the top of the cell being stepped back immediatelyover the outer rank so that all the jets of both ranks are accessiblethrough openings in the side of the cell, the cell being formed at thebottom with a space common to the filaments from all said jets, andmeans for collecting all said filaments in tow form.

3. Apparatus according to claim 1, comprising a tow-collecting devicefor collecting the filaments from all the jets in the form of a singletow.

4. Apparatus according to claim 1, comprising partitions in the upperpart of the cell, dividing said cell into sub-cells all openingdownwards into the common space.

5. Apparatus according to claim 1 comprising a pair of doors disposed atthe bottom of the cell to facilitate manipulation of the filaments, saiddoors, when closed, leaving a restricted outlet for the passage of thefilaments.

6. Apparatus according to claim 1, wherein the bottom of the cell is inthe form of an inverted pyramid whose apex is truncated to form anoutlet for all the filaments.

'7. Apparatus according to claim 6 comprising principal suction meansimmediately above the inverted pyramid at the bottom of the cell andauxiliary means for the withdrawal or introduction of setting mediumclose to the truncated apex Of said pyramid.

8. Apparatus according to claim 1 comprising suctionmean's disposednearthe bottom of the I cell for the withdrawal of gaseous settingmedium from the cell.

9. Apparatus according to claim 1 comprising dope-heating means forheating the film-forming liquid to be extruded from the jets. 1

10. Apparatus according to claim 9, wherein the dope-heating meansaredisposed in the top of the spinning cell within the area of the inner..-most rank of jets.

11. Apparatus according to claim9 comprising suction means disposednear. the bottom .of the cell for the withdrawal of gaseous settingmedium from the cell.

12. Apparatus according to claim 1 comprising a closed inner shell,below and within the area of the innermost rank of jets, which is not incommunication with the part of the cell through which the filamentspass.

13. Apparatus according to claim 12 comprising partitions in the upperpart of the cell terminating part-way down the inner shell, dividingsaid cell into sub-cells all opening downwards into the common spacesurrounding said shell.

14. Apparatus according to claim 2 comprising partitions in the upperpart of the cell, dividing said cell into sub-cells all openingdownwards into the common space.

15. Apparatus according to claim 14 comprising suction means disposednear the bottom of the cell for the withdrawal of gaseous setting mediumfrom the cell.

16. Apparatus according to claim 2 wherein the bottom of the cell is inthe form, of an inverted pyramid whose apex is truncated to form anoutlet for all the filaments, said outlet comprising a pair of doors tofacilitate manipulation of the filaments, said doors, when closed,leaving a restricted outlet for the passage of the filaments.

17; Apparatus according to claim 2.. wherein the bottom of the cell isin the form of an inverted pyramid whose apex is truncated to form anoutlet for all the filaments, said apparatus comprising principalsuction means immediately above said inverted pyramid for the withdrawalof gaseous setting medium from the cell and auxiliary means for thewithdrawal or introduction of setting medium close to the truncated apexof said pyramid.

18. Apparatus according to claim 2 comprising dope-heating means forheating the film-forming liquid to be extruded from the jets.

19. Apparatus according to claim 18 comprising suction means disposednear the bottom 01 the cell for the withdrawal of gaseous setting mediumfrom the cell.

20. Apparatus according to claim 19 wherein the bottom of the cell is inthe form of an inverted pyramid whose apex is truncated to form anoutlet for all the filaments, said apparatus comprising principalsuction means immediately above said inverted pyramid for the withdrawalof gaseous setting medium from the cell and auxiliary means for thewithdrawal or introduction of setting medium close to the truncated apexof said pyramid.

21. Apparatus according to claim 20 wherein the dope-heating means aredisposed in the top of the spinning cell within the area of theinnermost rank of jets.

22. Apparatus according to claim 21 comprising a closed inner shell,below and within the area of the innermost rank of jets, which is not incommunication with the part of the cell through whichthe filaments pass.

23. Apparatus according to claim .22 comprising partitions in the upperpart of the cell, terminating part-waydown the inner shell, dividingsaid cell into sub-cells all opening downwards into the commonspacezsurrounding said shell.

24;;Apparatus according to claim 23 comprising apair of "doors disposedat the bottom of the cell to facilitate manipulation of thefilaments,:said :d'oors, when closed, leaving a restricted outlet .for the passageof the filaments, and a towcollecting device for collecting, .in'theform of a single tow, the filaments from all the jets-emerg- "ing fromsaid restricted outlet.

25. Apparatus according to claim 2 comprising a closed inner shell,below and within the area of the innermost rank of jets, which is not incommunication with the part of the cell through whichithe'filamentspass.

WILLIAM IVAN TAYLOR.

No references cited.

1. AN APPARATUS FOR THE PRODUCTION BY DRY SPINNING OF A HEAVY BUNDLE ORTOW OF CONTINUOUS FILAMENTS, SAID APPARATUS COMPRISING A VERTICALSPINNING CELL, A PLURALITY OF RANKS OF MULTI-ORIFICE JETS IN THE UPPERPART OF THE CELL, ONE RANK WITHIN ANOTHER, EACH RANK CONSISTING OF ANUMBER OF JETS ARRANGED ROUND THE MIDDLE OF THE CELL, THE JETS OF EACHINNER RANK BEING AT A HIGHER LEVEL THAN THOSE OF THE RANK IMMEDIATELYOUTSIDE IT, AND THE TOP OF THE CELL BEING STEPPED BACK SO THAT ALL THEJETS ARE ACCESSIBLE THROUGH OPENINGS IN THE SIDES OF THE CELL, THE CELLBEING FORMED AT THE BOTTOM WITH A SPACE COMMON TO THE FILAMENTS FROM ALLSAID JETS, AND MEANS FOR COLLECTING ALL SAID FILAMENTS IN TOW FORM.